The above chart is from PCGS showing the coin serial number when put into PCGS coin look up chart. As all the population numbers for the WTC is not know by me or by PCGS this is the best we can do.

I would say one of the best coins on E-bay right now, a 2001 $50 Gold MS70. I think its the 2nd time I see a 2001 1oz MS70 coin on E-bay first time was the full set of WTC 2001 MS70 all 4 coins. Its a great looking coin and I am sure the buyer of this coin will look at this historic WTC coin as a true steal at the current price. If you can find this coin on E-Bay look at all the WTC coins that are on there if you remember to search in E-Bay stores.